Means for attaching sprocket-wheels to crank-shafts.



\ No. 627,597. Patented June 27, I899.

B. W. SCOTT. MEANS FOR ATTACHING SPROCKET WHEELS T0 CRANK SHAFTS.

(Application filed Aug. 26, 1898.)

[No Model.)

Y Z %VTOR.

I I 'f Attorneys.

a yL/K a UNITED STATES PATENT OFFICE.

BURTON w. scoTT,- or DETROIT, MICHIGAN.

MEANS FOR ATT'ACHING SPROCKET-WHEELS TO CRANK-SHAFTS.

SPECIFICATION forming-part of Letters Patent No. 627,597, dated June 27,1899.

Application filed August 26, 1898.

To all whom it may concern:

Be it known that I, BURTONNV, SCOTT, a citizen of Canada, residing atDetroit, in the county of Wayne, State of Michigan, have inventedcertain new and useful Improvements in Means for AttachingSprocket-\Vheels to Crank- Shafts; and I do declare the following to bea full, clear, and exact description of the invention, such as willenable others skilled in the art to whichit appertains to make and usethe same, reference being had to the accompanying drawings, and to theletters of reference marked thereon,which form a part of thisspecification. I

This invention relates to means for attaching the sprocket-wheel to thecank-shaft of a bicycle; and it consists in the construction andarrangement of parts hereinafter more fully set forth.

The object of the invention is to provide simple and efficient means forsecurely attaching the sprocket-wheel to the crank-shaft in such manneras to enable said sprocketwheel to be readily removed, the arrangementbeing such that the operation of securing the sprocket-wheel upon theshaft also looks one of the-bearing-cones and secures the crank inplace. This object is attained by the mechanism illustrated in theaccom:v panyin g drawings, in which- Figure l is a sectional viewthrough the crank-hanger, bearing,-and sprocket-wheel of a bicycle, theshaft and bearing-cones being in elevation and a portion of the crankand shaft being broken away. Fig. 2 is-an elevation of the end of theshaft and cone, showing the milling on opposite sides of the shaft andby dotted lines the locking-wedges lying thereon. Fig. 3 is an elevationof the hub of the sprocket-wheel looking from the inner side, showingthe beveled recesses in the bore which receive the locking-Wedges. Fig.4 is an elevation of said wedges, showinga side, end, and plan viewthereof.

Referring to the letters of reference, A designates the barrel of anordinary crankhanger, in which are the ball-cases A, carrying the ballsA".

B designates the crank-shaft, having the threaded end portions a for thereception of the bearing-cones O C. The crank D in the constructionshown is formed integral with Serial No. 689,573. (No model.)

the shaft. The end of the shaft opposite from the crank D is providedwith a threaded bore 79. Adjacent to the cone 0 the shaft is milled onopposite sides, producing the parallel flat surfaces 0, which stand in aplane at right angles to the crank D.

Two quadrangular keys (I, having an outer beveled face 'e, are adaptedto lie with their straight side against the milled faces a of theshaftand tobear against or rest upon the cone 0.

The sprocket-wheel E is provided with a bore f,- passing through the hubthereof, adapted to receive the shaft B, and with two opposedrectangular recessesg,leading from said bore, adaptedto embrace the keysd and having a beveled face e, the incline of which extendsin wardthrough the inner face of the hub of said wheel and is adapted tocoincide with the beveled face of the keys (1. The sprocket-wheel isadapted to .be slipped over the end of the shaft, so that the recesses gin the hub thereof shall receive the keys (1, the inclined face e of therecesses in said sprocketwheel engaging the inclined face 6 of saidkeys, so as to wedge the sprocket-wheel tightly upon the shaft andprevent its turning thereon.

,F designates an annular washer, which is slipped over the outer end ofthe shaft 13 and bears against the outer face of the sprocketwheel.

same time forcing said keys against the cone 0, locking said cone uponthe shaft by the same operation which looks the sprocket wheel andtightens the crank G. The stem of the crank G is screwed into the shaftuntil the shoulder a thereon bears forcibly against the washer F, whenthe boss h on said crank, in which is a threaded aperture, is brought toregister with the screw h, which passes thron gh the arm 11 of thesprocket-wheel and is adapted to enter said boss, whereby said crank issecurely locked from unscrewing.

To insure a proper alinement of the cranks, the recesses g are formed inthe bore of the hub of the sprocket-wheel so as to register with the armH of said wheel, through which the locking-screw h passes, so that thecrank G when brought into position to receive the screw h will alwaysstand in alinement with the crank D.

To enable the crank G to be always brought into proper position toreceive the screw h, the cone 0 may be so adjusted on the threadedportion of the shaft as to allow the crank G when screwed tightly intoplace to stand in such position as to receive the screw h.

After the sprocket-wheel has been properly lock ed upon the shaft thebearing may be adjusted through the medium of the cone C, which is freeto be adjusted after the crank G is locked and which after adjustmentmay be locked by the jam-nut C".

By means of the construction above set forth it will be seen that thesprocket-wheel, although firmly locked to the crank-shaft, is madereadily removable therefrom bysimply unscrewing the crank G, when thewasher F and the sprocket-wheel E may he slipped from the shaft,enabling an easy exchange of sprocket-wheels, if desired, or the readyremoval of the crank-shaft from the hearing by simply unscrewing thecone O therefrom. \Vhen setting up the bearing, said parts may bequickly assembled and easily seen red in place, as before described.

Having thus fully set forth this invention, what is claimed is- 1. Thecombination of a crank-shaft of a bicycle, said shaft having a flattenedface, a beveled key adapted to lie with its straight side against theflat face of said shaft, a sprocket-wheel apertu red to receive theshaft and having a recess which receives said beveled key, and a cranksecured upon the projecting end of said shaft and bearing forciblyagainst the outer face of the sprocket-wheel.

2. The combination with the crank-shaft of a bicycle having a flattenedface and a threaded bore in the end thereof, a cone threaded upon saidshaft, a beveled key lying against the flat face of the shaft andbearing upon said cone, a sprocket-wheel apertured to receive the shaftand having a recess in which said beveled key is adapted to lie, awasher fitting on the outer end of the shaft and lying against the faceof the sprocketwheel, a crank adapted'to be screwed into the threadedbore of the shaft and to bear forcibly against said washer,'and meansfor locking said crank.

In testimony whereof I sign this specification in the presence of twowitnesses.

BURTON \V. SCOTT.

Witnesses:

E. WHEELER, M. A. MARTIN.

